Hi all, it's me again with 'serial' problems ;) I got the netX serial driver working quite fine. So the next step was to try out printf (I was using diag_printf before, which works flawlessly). I enabled asserts, tracing and io init debugging. Stdio is still on the default /dev/ttydiag (which works fine on the linux synthetic target). But on my real hardware, I directly get an assertion: ASSERT FAIL: <3>stream.cxx[603]virtual Cyg_ErrNo Cyg_StdioStream::write() Stream object is not a valid stream! I debugged that a few days ago, so it's somewaht summed up out of my mind: I stepped a bit through the constructors that fire up stdin and stdout. The assertion seems to be raised because the magic word hasn't been written. I trapped that down to the fact that the buffer used by the stream has no size (i.e. is 0). And that's the point were I left, because I had no idea, why this could be the case. I also tried routing STDIO to /dev/ser0 and /dev/tty0, which resulted in the same assertion (but I didn't step into the constructors in these scenarios). Find my minimal minimal config's attached, I'm importing for the scenario. Any hints on how to debug this any further or pointers what i'm missing in my config are greatly appreciated. Cheers, Manuel -- Manuel Borchers Web: http://www.matronix.de eMail: manuel@matronix.de